The simple, by-the-book method is to give him a BAB of +10, Luck +10 which he always uses on attacks, a BDB of at least +5 so that he can use All-Out Attack to get another +5, a weapon that does +10 so that he can Accurate Attack it for 5 or so, Attack Focus, and the Area Extra flawed to 1, so that he always hits an area of five feet -- meaning that, with an attack bonus of 10+10 luck +5 all-out +5 accurate +1 focus = +31 to hit -- he is almost always going to make a direct hit, and will, even on a miss, hit the area, forcing a Reflex save for half damage (and on a fail, full damage anyway).